[commands] Bugfix on the teardown function call.
[commands] Bugfix on the teardown function call.

Harmon758/discord.py,imayhaveborkedit/discord.py,Harmon758/discord.py,khazhyk/discord.py,mgardne8/discord.py,rapptz/discord.py,Rapptz/discord.py,variablehair/Eggplantato